Kinetics and mechanisms of plasmachemical processes in HCl mixtures with inert and molecular gases

I carry out my scientific work at the department of Technology of Devices and Electronic Techniques Materials. My supervisor is Alexander Mihajlovich Efremov, he is a Doctor of Chemistry and professor of my department.

The basic part of my research is a computer modeling and the comparison of the data obtained and the experimental data. In the experimental parts of our work we use probe techniques (Langmjur probes) and spectroscopic methods of research. In the course of modeling numerical integration by the method of left triangles, the systems of linear algebraic equations and a method of iterations are used.

The algorithm of modeling was based on the joint solution of the following equations: 1. The steady-state Boltzmann kinetic equation without taking into account both electron-electron collisions and the second-order impacts; 2. The plasma conductivity equation; 3. The balance equations for neutral and charged particles in a steady-state approximation; 4. The quasi-neutrality equation.

At first we worked with pure HCl plasma, then with its mixtures with Ar, H2 and He. In our work, we carried out the investigations of plasma parameters and active particles kinetics in HCl and in its mixtures in direct current glow discharges. We used the experimental methods and self-consistent six- component plasma modeling based on the solution of Boltzmann kinetic equation. The model showed a good agreement with the experimental values of E/N reduced electric field strength. And it provided an adequate description of the basic kinetic effects which determine the steady-state plasma parameters and the composition of neutral particles in mixtures with HCl. It was found that the increase of Ar, H2 or He percent content in an initial mixture is not accompanied by additive redistribution of the ways of electrons energy loss by nonelastic impacts. This leads to the enrichment of EEDF Electron energy distribution function with high energy electrons. All these facts agree with the peculiarities of formation-decay kinetics and transport of neutral and charged species in the mixtures with HCl. Later we plan to obtain the same data for some other mixtures.

The accuracy of modeling depends on the initial data. Rate constants, cross sections, data search and the analysis of their adequacy to the experimental data are the complicated points of my work.

Practical application of my calculations is an optimization of plasmachemical etching processes, the so-called predictive analysis.

Yudina A.V.